JPS63168944A - X-ray generator - Google Patents

Abstract

PURPOSE:To extend the life of this device by forming the wall face of a capillary with a dielectric substance and drawing out the wall face in response to the consumption of the wall face. CONSTITUTION:When a capacitor Cd is charged and the sufficiently large voltage is applied to an insulator 8, the dielectric substance 9 facing a capillary 2 is evaporated by the creeping discharge of the capillary 2 to generate plasma 5. In this case, when an electron beam is radiated from a cathode 6 to the plasma 5, the temperature of the plasma 5 rises, the plasma density is increased, and X-rays 7 are generated. Part of the surface of the dielectric substance 9 facing the capillary 2 generates plasma by the creeping discharge, thus the dielectric substance is reduced as much. Therefore, the dielectric substance 9 is moved toward the center of the capillary 2 as much as the quantity generating plasma. Accordingly, the consumption of the dielectric substance resulting from the generation of plasma can be compensated by the drawing out of the dielectric substance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an X-ray generator that generates highly accurate and highly efficient pulsed X-rays.

[Prior Art] Recently, development of an X-ray exposure apparatus using X-rays has been progressing as an apparatus for forming fine patterns on samples such as semiconductor wafers and masks. The X-ray generating device used in this X-ray exposure apparatus generally uses a method in which a high-speed electron beam collides with a target to generate X-rays from the target. However, according to this method, the X-ray generation efficiency is as low as about 0.1%, and the target dissolves when the intensity of the electron beam collided with the target is increased, so there is a limit to obtaining high-power X-rays. there were.

Therefore, an X-ray generator using creeping discharge has been devised to obtain high-output X-rays.

The general structure of this X-ray generator (capillary plasma X-ray source) is shown in FIG.

That is, a cylindrical insulator 1 made of polyethylene has a capillary (tubular space) 2 passing through its center, and electrodes 3 and 4 are provided on both sides of the insulator 1. Ra and Rb are resistors, Cb and Cd are capacitors, and a DC high voltage -HV is applied to one end of the resistor Ra.

When the capacitor Cd is charged with this structure and a sufficiently large voltage is applied to the insulator 1, the polyethylene constituting the insulator 1 is evaporated by creeping discharge of the capillary 2, and plasma 5 is generated. At this time, when the plasma 5 is irradiated with an electron beam from the cathode 6, the temperature of the plasma 5 increases,
In addition, the plasma density increases and X-rays 7 are generated.

[Problems to be Solved by the Invention] However, in such a conventional method, the polyethylene constituting the insulator 1 is consumed, so the diameter of the capillary 2 becomes large. For example, when a voltage of about 50 KV is applied and discharge is performed about 300 times, the diameter of the capillary, which was initially 1 mm, becomes 3 mm. As the capillary diameter increases, the plasma density decreases and the generated
Since the intensity of the rays is reduced, the conventional method has the disadvantage that the life of the X-ray generator is short.

In view of the drawbacks of the above-mentioned conventional examples, an object of the present invention is to provide a high-output
It is an object of the present invention to provide a capillary type X-ray generating device that can maintain the ability to generate rays for a long period of time.

[Means and actions for solving the problem
The ray generator is a capillary plasma X-ray source that generates X-rays by creating high-density plasma in a capillary by creeping discharge and injecting a high-speed electron beam into the plasma.
The capillary is constituted by a dielectric wall divided into a plurality of parts, and the dielectric can be drawn out.

Therefore, the consumption of the dielectric material due to plasma formation can be compensated for by feeding out the dielectric material.

[Example] Hereinafter, the present invention will be explained in detail using the drawings. Note that parts common or corresponding to those of the conventional example shown in FIG. 3 are denoted by the same reference numerals.

FIG. 1 shows the configuration of an X-ray generator according to an embodiment of the present invention. In the same figure, Ra and Rh are resistances, Cb and Cd
is a capacitor, 2 is a capillary, 3.4 is an electrode, 5 is a generated plasma, 6 is a cathode, 7 is an X-ray, 8 is an insulator,
9 is a dielectric material.

As can be seen from the figure, the capillary 2 is composed of four square prism insulators 8 and a dielectric 9 in contact with the insulators. The capillary 2 is surrounded by a dielectric 9. The dielectric 9 is an electrically insulating material containing an element that should emit X-rays in a predetermined wavelength range (for example, polyethylene or the like if carbon X-rays are required). The insulator 8 may be made of the same material as the dielectric 9, but may be made of a different material from the dielectric 9 (for example, alumina AIL203) as long as it is an insulator. Electric i3, 4,
The cathode 6, insulator 8, and dielectric 9 are housed in a vacuum container.

Next, the operation of the apparatus shown in FIG. 1 will be explained.

When the capacitor Cd is charged and a sufficiently large voltage is applied to the insulator 8, the dielectric 9 facing the capillary 2 is evaporated by the creeping discharge of the capillary 2, and plasma 5 is generated. At this time, when the plasma 5 is irradiated with an electron beam from the cathode 6, the temperature of the plasma 5 increases and the plasma density increases. Then, X-rays 7 are generated. The process up to this point is the same as the conventional type. However, since a part of the surface of the dielectric 9 facing the capillary 2 is turned into plasma by the creeping discharge, the number of speaking bodies is reduced. Therefore, the dielectric 9 is moved toward the center of the capillary 2 by the amount that has been turned into plasma.

This situation is shown in FIG. However, in the figure, only the insulator 8 and dielectric 9 that constitute the capillary 2 are shown.
Electrodes etc. were omitted. As shown in the figure, the dielectric 9 is moved in the direction indicated by the arrow.

This movement of the dielectric 9 may occur every single discharge or several times.
This may be carried out after an appropriate number of discharges every several tens of times, or may be carried out at an appropriate time by measuring the degree of reduction in the dielectric. There are various measurement methods, but for example, the degree of reduction can be determined by moving two opposing dielectrics toward the center of the capillary until they come into contact with each other, and from the distance traveled. Furthermore, when moving the dielectric, increasing the distance between the insulators 8 makes it easier to move the dielectric 9.

[Modifications of Embodiments] Many electrical circuits have been devised for plasma generation used in the capillary plasma X-ray source as described in the above embodiments. The present invention provides such a capillary plasma
It can be configured by any electric circuit for a radiation source, and is not limited to this electric circuit. For example, FIG. 4 shows a modification of the apparatus shown in FIG. 1, but the present invention can also be configured as a capillary plasma X-ray source having such a circuit.

Furthermore, many modifications can be made to the insulator 8 and dielectric 9 constituting the capillary 2, as shown in FIGS. 5 and 6, for example. FIG. 5 is a sectional view at the center of the capillary, and corresponds to the section AA in FIG. FIG. 6 shows an example of an X-ray source in which the dielectric 9 is also divided into three in the direction perpendicular to the capillary 2, and this dielectric 9 and the insulator 8 are shown in FIG. 6-2.

If the dielectric 9 is divided also in the direction perpendicular to the capillary as shown in FIG. 6, even if the dielectric decreases locally, it can be compensated for.

[Effects of the Invention] As explained above, according to the present invention, in a thin tube type X-ray generator, the wall surface of the capillary is formed of a dielectric material, and the wall surface is drawn out as the wall surface wears out. Unlike the conventional type, the output of X-rays does not decrease due to an increase in the diameter of the capillary, and high-output X-ray generation capability can be maintained, and the life of the X-ray generator can be extended.

[Brief explanation of the drawing]

FIG. 1 is a structural diagram showing the configuration of an X-ray generator according to an embodiment of the present invention; FIG. 2 is a perspective view showing how the dielectric 9 is moved in the device shown in FIG. 1; FIG. 3 shows a conventional capillary plasma X-ray source, and FIGS. 4 to 6 show modified examples of the present invention. 1: Dielectric, 2: Capillary, 3.4: Electrode, 5: Plasma, 6: Cathode, 7: X-ray, 8: Insulator, 9: Dielectric, Patent Applicant Canon Co., Ltd. Agent Patent Attorney Tatsu Ito Male agent Patent attorney Tetsuya Ito b Figure 2 b Figure 3 Figure 4 Figure 5 Cb Figure 6-1 Figure 6-2

Claims (1)

[Claims] 1. A capillary space formed by surrounding it with a plurality of bulk dielectrics, and a means for generating plasma in the capillary space by causing a creeping discharge along the wall of the capillary space. and means for injecting electrons into the plasma. 2. The X-ray generating device according to claim 1, wherein each of the dielectrics is movable toward the center of the tubular space.